Modified epoxy resin composition used in high solids coating

ABSTRACT

This invention relates to a cardanol modified epoxy resin composition, especially, relates to a cardanol and/or dihydric phenol modified epoxy resin composition, a process making thereof and its application in low VOC high solids coating.

FIELD

This invention relates to a cardanol modified epoxy resin composition,especially, relates to a cardanol and/or dihydric phenol modified epoxyresin composition, and its application in low volatile organic compounds(VOC) high solids coating.

BACKGROUND

Epoxy based anti-corrosion coatings are widely used for the protectionof metal and concrete substrates. Due to increasing awareness ofenvironmental protection and severe environmental requirements, low VOCcoating system attracted more and more attention from both paintproducer and end customers. From technical view of point, one approachto achieve low VOC coating is to prepare high solids coating withreduced solvent addition using low viscosity epoxy.

In the past, solid epoxy resins such as D.E.R.™ 671 (commercial productof the Dow Chemical Company) are widely used in anti-corrosion coatings.However, D.E.R.™ 671 is not suitable for the low VOC high solids epoxycoatings because of its solid state. Large amount of solvent is demandedto dissolve and dilute them which hinder the epoxy resin from low VOChigh solids applications. Usually, D.E.R.™ 671 is supplied with 25%xylene and the resin solution commercial grade name is D.E.R.™ 671-X75.

The coating based on liquid epoxy such as D.E.R.™ 331 (commercialproduct of the Dow Chemical Company) requires less solvent, however, isquite brittle. This is a critical issue for an anti-corrosion coatingwhich requires high flexibility and good adhesion on substrates.

Reactive diluents can significantly reduce the viscosity of the systembut at the same time compromise the reactivity or functionality of theresin part. This brings long drying time or poor chemical resistance tothe coating. Meanwhile, reactive diluents are always more expensive thanepoxy resins.

Fatty acid modified epoxy resins are one kind of popular modified epoxyin low VOC high solids coatings. However, the ester group generated fromthe reaction between epoxy and acid has the risk to hydrolyse, sinceester group is inclined to hydrolyze.

It is therefore, still desired in the art an epoxy resin giving bothlower viscosity and higher flexibility so that it is very suitable forthe low VOC high solids coating application.

SUMMARY

The present invention provides an epoxy resin composition comprising,based on the total weight of the epoxy resin composition, i) from 10% to90% by weight of a liquid epoxy resin of formula (I); and ii) from 10%to 90% by weight of a compound of formula (V);

wherein n is independently 0 or 1; R is independently H or —CH₃; and R₁is —C₁₅H₂₅, —C₁₅H₂₇, —C₁₅H₂₉, or —C₁₅H₃₁.

Optionally, the epoxy resin composition of the present invention furthercomprises, based on the total weight of the composition, from 10% to70%, preferably from 15% to 55% by weight of a compound of formula (VI):

wherein x is 1 or 2; n is independently 0 or 1; each R is independentlyH or CH₃; and R₁₁ is a fragment of a dihydric phenol.

R₁₁ is represented by formula (VII),

wherein R₂ is independently H or a C₁-C₁₅ alkyl or alkenyl group; or

is represented by formula (VIII),

wherein each R is independently H or —CH₃; and R₃ to R₁₀ is eachindependently H or a C₁-C₆ alkyl group.

The present invention further provides a low VOC high solids coatingcomprising the modified epoxy resin composition, and one or more of ahardener, an organic solvent, a pigment, a filler, and a flow controlagent.

DETAILED DESCRIPTION

The suitable raw material liquid epoxy resin is from 60% to 95%,preferably, from 70% to 90% by weight based on the total weight of themixture, of a diglycidylether of bisphenol, such as Bisphenol A andBisphenol F, wherein the epoxy equivalent weight (EEW) of the rawmaterial liquid epoxy resin is from 150-250, preferably from 160-220,more preferably from 170-200. The epoxy resin is in liquid state.

The suitable raw material liquid epoxy resin is in the chemical formula(I) below,

wherein n is 0 or 1. Most preferably, n is 0. The average n value of theliquid epoxy resin (I) is from 0 to 1. Preferably, it is from 0 to 0.5.Most preferably, it is from 0 to 0.3. R is independently H or —CH₃.

As used herein, the term “liquid epoxy resin” refers to the resin in aliquid state without adding any solvent. To achieve liquid state, theEpoxy Equivalent Weight (EEW) of the liquid epoxy resin is in the rangeof 150 to 250. Preferably, the EEW of the liquid epoxy resin is from 170to 220. More preferably, it is from 175 to 200.

Suitable examples of the raw material liquid epoxy resin includes, butnot limited to D.E.R.™ 331, which is a commercial product of the DowChemical Company; D.E.R.™ 354 of the Dow Chemical Company; D.E.R.™ 332of the Dow Chemical Company; D.E.R.™ 330 of the Dow Chemical Company;D.E.R.™ 383 of the Dow Chemical Company.

The raw material liquid epoxy resin is reacted with “cardanol”.“Cardanol” is one component of cashew nut shell liquid (CNSL), an oilisolated from the shell of the cashew nut. The structure of cardanol isa phenol containing one hydroxyl group, and an aliphatic side chain R₁in the meta-position, as shown in the chemical formula (II). R₁ is—C₁₅H₂₅, —C₁₅H₂₇, or —C₁₅H₂₉. The content range of the cardanol is from5% to 40%, preferably from 10% to 30%, by weight based on the totalweight of the reacting mixture.

Optionally, the raw material liquid epoxy resin could further be reactedwith, from 0.1% to 20%, preferably from 0.1% to 15%, by weight based onthe total weight of the mixture, a dihydric phenol. The term “dihydricphenol” refers to a phenolic compound containing 2 hydroxyl groups. Asused herein, the dihydric phenol refers to either of the two structuresillustrated: a phenol with two hydroxyl groups on one benzene ring inthe chemical formula (III), wherein R₂ is H or a C₁-C₁₅ aliphatic chain;or a composition containing two benzene ring each with one hydroxylgroup on it in the chemical formula (IV), wherein R is H or —CH₃; and R₃to R₁₀ is H or a C₁-C₆ aliphatic chain.

One example of the phenol contains two hydroxyl groups is cardol.“Cardol” is also one component of cashew nut shell liquid (CNSL). Thestructure of cardol is a 1,3-Dihydroxybenzene with a side chain atposition 5, the side chain is —C₁₅H₂₅, —C₁₅H₂₇, or —C₁₅H₂₉.

Another example of a phenol containing two hydroxyl groups isresorcinol.

The examples of compositions containing two benzene rings each with onehydroxyl group in the chemical formula (IV) are Bisphenol A andBisphenol F.

The modified epoxy resin composition of the present invention isprepared according to known methods, for example, a modificationreaction of an epoxy resin with phenols, wherein the reactive hydrogenatom is reactive with an epoxy group in the epoxy resin.

The modification reaction may be conducted in the presence or absence ofa solvent with the application of heating and mixing. The modificationreaction may be conducted at atmospheric, superatmospheric orsubatmospheric pressures and at temperatures of from 20° C. to 260° C.,preferably, from 80° C. to 200° C., and more preferably from 100° C. to180° C.

The time required to complete the modification reaction depends upon thefactors such as the temperature employed, the chemical structure of thecompound having more than one reactive hydrogen atom per moleculeemployed, and the chemical structure of the epoxy resin employed. Highertemperature may require shorter reaction time whereas lower temperaturerequires a longer period of reaction time.

In general, the time for completion of the modification reaction mayrange from 5 minutes to 24 hours, preferably from 30 minutes to 8 hours,and more preferably from 30 minutes to 4 hours.

A catalyst may also be added in the modification reaction. Examples ofthe catalyst may include basic inorganic reagents, phosphines,quaternary ammonium compounds, phosphonium compounds and tertiaryamines. Particularly, catalysts suitable to the present inventioninclude, but not limited to, NaOH, KOH, ethyl triphenyl phosphoniumacetate, imidazole, and triethylamine. The catalyst may be employed inquantities of from 0.01 percent to 3 percent, preferably from 0.03percent to 1.5 percent, and more preferably from 0.05 percent to 1.5percent by weight based upon the total weight of the epoxy resin.

Other details concerning a reaction useful in preparing the modifiedepoxy product of the present invention are provided in U.S. Pat. No.5,736,620 and in Handbook of Epoxy Resins by Henry Lee and Kris Neville,incorporated herein by reference.

In one embodiment of the present invention, the raw material epoxyresin, cardanol, and optional dihydric phenol are mixed in proper amountas described above, and dissolved and heated under the proper conditionof modification reaction as described above to form the modified epoxyresin composition of the present invention.

The modified epoxy resin composition of the present invention comprises,based on the total weight of the modified epoxy resin composition: i)from 10% to 90%, preferably from 30% to 70% by weight of at least oneliquid epoxy resin in the chemical formula (I) below

andii) from 10% to 90%, preferably from 30% to 70% by weight of at leastone cardanol modified epoxy compound in the chemical formula (V) below

wherein n of the liquid epoxy resin (I) and the cardanol modified epoxycompound (V) is 0 or 1. Most preferably, n is 0. The average n value isindependently from 0 to 1. Preferably, it is from 0 to 0.5. Mostpreferably, it is from 0 to 0.3. R is independently H or CH₃. R₁ is—C₁₅H₂₅, —C₁₅H₂₇, or —C₁₅H₂₉.

The EEW of the liquid epoxy resin (I) is in the range from 150 to 250,the preferred EEW of the liquid epoxy resin is from 170 to 220, and morepreferred EEW of the liquid epoxy resin is from 175 to 200.

The EEW of the cardanol modified epoxy (V) is in the range from 550 to850, the preferred EEW of the cardanol modified epoxy is from 580 to800, and more preferred EEW of the cardanol modified epoxy is from 600to 750.

In another embodiment, the epoxy resin composition of the presentinvention comprises, based on the total weight of the composition, from20% to 75%, preferably from 35% to 60% by weight of the compound offormula (I), from 20% to 75%, preferably from 35% to 60% by weight ofthe compound of formula (V), and from 0.1% to 20%, preferably from 0.1%to 5% of a compound of formula (X):

wherein n is 0 or 1; R is independently H or —CH₃; and R₁ isindependently —C₁₅H₂₅, —C₁₅H₂₇, or —C₁₅H₂₉.

Optionally, the epoxy resin composition of the present invention mayfurther comprises, based on the total weight of the composition, of from10% to 70%, preferably from 15% to 55% by weight of a dihydric phenolmodified epoxy compound of formula (VI):

wherein x is 1 or 2, preferably x is 1; each n is independently 0 or 1,more preferably n is 0; R is independently H or CH₃; and R₁₁ is afragment of a dihydric phenol.

In yet another embodiment, the epoxy resin composition of the presentinvention further comprises, based on the total weight of thecomposition, from 0.1% to 15%, preferably from 0.1% to 5% by weight of acompound of formula (IX):

wherein x is 1 or 2, more preferably x is 1; n is independently 0 or 1,more preferably n is 0; each R is independently H or CH₃; R₁ isindependently —C₁₅H₂₅, —C₁₅H₂₇, or —C₁₅H₂₉, and R₁₁ is a fragment of adihydric phenol.

The EEW of the dihydric phenol modified epoxy is in the range from 400to 700, the preferred EEW of the dihydric phenol modified epoxy is from430 to 650, more preferred EEW of the dihydric phenol modified epoxy isfrom 450 to 600.

The fragment of a dihydric phenol, R₁₁, is a compound represented byformula (VII),

wherein R₂ is independently H or a C₁-C₁₅ alkyl or alkenyl group.

In a more preferred embodiment, the fragment of a dihydric phenol, R₁₁,is a cardol.

In another embodiment, the fragment of a dihydric phenol, R₁₁, is acompound represented by formula (VIII),

wherein each R is independently H or —CH₃; R₃ to R₁₀ is eachindependently H or a C₁-C₆ alkyl group.

A “coating” according to the present invention will generally beunderstood as a composition that, when cured, can form a substantiallycontinuous film or layer. It will be appreciated that when the presentmodified epoxy resins are used in a coating according to the presentinvention, they can react with hardener, and form all or part of thefilm-forming resin of the coating. That is, the modified epoxy resindescribed herein will react, thereby contributing to the cure of thecoating. In certain embodiments, one or more additional film-formingresins are also used in the coating. The hardener may be selected from,for example, aminoplasts, polyisocyanates including blocked isocyanates,polyepoxides, beta-hydroxyalkylamides, polyacids, anhydrides,organometallic acid-functional materials, polyamines, polyamides, andmixtures of any of the foregoing. Amine based hardeners are preferred.

In one embodiment, the coating composition comprises a modified epoxyresin composition of the present invention, and with from 20% to 90%,preferably from 30% to 60% by weight, based on the total weight of thecoating composition, a phenalkamine hardener.

Phenalkamine is the condensation product of cardanol, formaldehyde, anda polyamine through the Mannich reaction. Suitable examples of thephenalkamine hardner includes, but not limited to, commercializedproduct, Cardolite™ NC 541, Cardolite™ NC 541LV, Cardolite™ NX 2015.When the epoxy resin was cured with phenalkamine hardener, the coatingformulation can be used in low temperature curing system.

The coating compositions may also include organic solvents. Suitablesolvents include glycols, glycol ether alcohols, alcohols, ketones, andaromatics, such as xylene and toluene, acetates, mineral spirits,naphthas and/or mixtures thereof “Acetates” include glycol etheracetates.

The coating composition is prepared with techniques which are well knownin the coating art. The coating composition may include pigments andfillers. Exemplary filler materials such as calcium carbonate, fumedsilica, precipitated silica, magnesium carbonate, talc, and the like.Exemplary pigments such as titanium dioxide, iron oxides, carbon blackand the like. The fillers and pigments may be used singly or incombination.

If desired, the coating compositions can comprise other optionalmaterials well known in the art of formulating coatings, such asplasticizers, anti-oxidants, hindered amine light stabilizers, UV lightabsorbers and stabilizers, flow control agents, thixotropic agents,organic cosolvents, reactive diluents, catalysts, grind vehicles, andother customary auxiliaries.

The coating composition may be applied by conventional applicationmethods such as, for example, brushing, roller application, and sprayingmethods such as, for example, air-atomized spray, air-assisted spray,airless spray, high volume low pressure spray, and air-assisted airlessspray.

The coating composition may be applied to a substrate such as, forexample, metal, plastic, wood, stone, glass, fabric, concrete, primedsurfaces, previously painted surfaces, and cementitious substrates.

The coatings of the present invention can be used alone, or incombination with other coatings. In one embodiment, the coatings aremulti-layer coatings comprising the coating compositions of the presentinvention as a primer, a tie coat and, optionally, Topcoat.

The coating composition of the present invention can be used inapplications including, but not limited to, marine coating and generalanti-corrosion coating.

The coating composition coated on the substrate is dried, or allowed todry, at a temperature of from −15° C. to 150° C., typically at roomtemperature.

EXAMPLES I. Raw Materials

MATERIALS FUNCTION CHEMICAL NAME SUPPLIER D.E.R. ™ 331 EpoxyDiglycidylether of Bisphenol A The Dow Chemical Company D.E.R. ™ 354Epoxy Diglycidylether of Bisphenol F The Dow Chemical Company D.E.R. ™664 UE Epoxy Diglycidylether of Bisphenol A The Dow Chemical CompanyD.E.R. ™ 671-X75 Epoxy (in xylene Diglycidylether of Bisphenol A The DowChemical Company solution) Ethyl triphenyl Catalyst Ethyl triphenylphosphonium phosphonium acetate (70 wt. % methanol acetate solution)Xylene Solvent Cardolite ™ NC Hardener Cardolite Cooperation 541LVCardolite ™ NC Hardener Cardolite Cooperation 541

II. Test Methods

TEST METHODS Resin Viscosity The Viscosities were tested using aBrookfield CAP 2000+ viscometer, 6# rotator, 400 rmp. Solution Viscosity10 parts by weight xylene was used to dissolve 90 parts by weight epoxyresin. The Viscosities were tested using a Brookfield CAP 2000+viscometer, 6# rotator, 400 rmp. Pot life The end of pot life wasdetermined as the time required for doubling the initial viscosity aftermixing with hardener. Drying Time Drying time was recorded using a BYKGardner Drying Recorder. Pendulum Hardness ASTM D-4366 Wedge bend ASTMD-522 Impact resistance ASTM D-2794 Anti-corrosion resistance ASTM B-117

Example 1

92 parts by weight D.E.R.™ 331 and 8 parts by weight cardanol were mixedunder nitrogen condition in a flask. After the mixture reached 90° C.,200 ppm ethyl triphenyl phosphonium acetate (70 wt. % methanol solution)was added as catalyst. The mixture was heated to 180° C. and kept atthis temperature for 2 hours. The epoxy resin A was obtained. Theproduct contained about 81 wt. % compound (I) and about 19 wt. %compound (V).

Example 2

85 parts by weight D.E.R.™ 331, 7.5 parts by weight cardanol and 7.5parts by weight cardol were mixed under nitrogen condition. After themixture reached 90° C., 300 ppm ethyl triphenyl phosphonium acetate (70wt. % methanol solution) was added as catalyst. The mixture was heatedto 170° C. and kept at this temperature for 3 hours. The epoxy resin Bwas obtained. The product contained about 57 wt. % compound (I), 17 wt.% compound (V) and 26 wt. % compound (VI).

Example 3

80 parts by weight D.E.R.™ 331 and 20 parts by weight cardanol weremixed under nitrogen condition. After the mixture reached 90° C., 400ppm ethyl triphenyl phosphonium acetate (70 wt. % methanol solution) wasadded as catalyst. The mixture was heated to 160° C. and kept at thistemperature for 4 hours. The epoxy resin C was obtained. The productcontained about 55 wt. % compound (I) and about 45 wt. % compound (V).

Example 4

65 parts by weight D.E.R.™ 331 and 35 parts by weight cardanol weremixed under nitrogen condition. After the mixture reached 90° C., 350ppm ethyl triphenyl phosphonium acetate (70 wt. % methanol solution) wasadded as catalyst. The mixture was heated to 180° C. and kept at thistemperature for 3 hours. The epoxy resin D was obtained. The productcontained about 20 wt. % compound (I) and about 80 wt. % compound (V).

Example 5

70 parts by weight D.E.R.™ 331, 15 parts by weight cardanol and 15 partsby weight cardol were mixed under nitrogen condition. After the mixturereached 90° C., 250 ppm ethyl triphenyl phosphonium acetate (70 wt. %methanol solution) was added as catalyst. The mixture was heated to 180°C. and kept at this temperature for 2 hours. The epoxy resin E wasobtained. The product contained about 14 wt. % compound (I), 34 wt. %compound (V) and 52 wt. % compound (VI).

Example 6

64 parts by weight D.E.R.™ 331, 30 parts by weight cardanol and 6 partsby weight cardol were mixed under nitrogen condition. After the mixturereached 90° C., 300 ppm ethyl triphenyl phosphonium acetate (70 wt. %methanol solution) was added as catalyst. The mixture was heated to 190°C. and kept at this temperature for 1 hour. The epoxy resin F wasobtained. The product contained about 11 wt. % compound (I), 68 wt. %compound (V) and 21 wt. % compound (VI).

Example 7

85 parts by weight D.E.R.™ 354, 10 parts by weight cardanol and 5 partsby weight resorcinol were mixed under nitrogen condition. After themixture reached 90° C., 200 ppm ethyl triphenyl phosphonium acetate (70wt. % methanol solution) was added as catalyst. The mixture was heatedto 180° C. and kept at this temperature for 4 hours. The epoxy resin Gwas obtained. The product contained about 43 wt. % c compound (I), 21wt. % compound (V) and 36 wt. % compound (VI).

Example 8

85 parts by weight D.E.R.™ 331, 10 parts by weight cardanol and 5% partsby weight bisphenol A were mixed under nitrogen condition. After themixture reached 90° C., 350 ppm ethyl triphenyl phosphonium acetate (70wt. % methanol solution) was added as catalyst. The mixture was heatedto 160° C. and kept at this temperature for 5 hours. The epoxy resin Hwas obtained. The product contained about 56 wt. % compound (I), 23 wt.% compound (V) and 21 wt. % compound (VI).

Comparative examples 1 and 2 were carried out substantially as describedin KR559055B1.

Comparative Example 1

In the flask equipped with a condenser and a stirrer were introduced49.6 parts by weight D.E.R.™ 331 and 50.4 parts by weight cardanol andthen the temperature was elevated up to 140° C. After the reaction wasmaintained for 5 hours, cooling was carried out. Catalyst was not usedin this example, so that reaction was not completely finished. D.E.R.™331 is a commercially available substitute for YD-128. The epoxy resin Iwas obtained. Gas chromatography-mass spectrometry (GC-MS) method showedunreacted cardanol monomer remained in epoxy resin I, and the cardanolmodified epoxy resin is in a range of less than 5 wt. % based on thetotal reaction product, epoxy resin I.

Comparative Example 2

In the flask equipped with a condenser and a stirrer were introduced89.3 parts by weight D.E.R.™ 664 UE and 10.7 parts by weight cardanoland then the temperature was elevated up to 140° C. Then after thereaction was maintained for 5 hours, cooling was carried out. D.E.R.™664 UE is a solid with n being around 6, and is a commercially availablesubstitute for YD-014. The epoxy resin J was obtained.

Comparative Example 3

97 parts by weight D.E.R.™ 331 and 3 parts by weight cardanol were mixedunder nitrogen condition. After the mixture reached 90° C., 150 ppmethyl triphenyl phosphonium acetate (70 wt. % methanol solution) wasadded as catalyst. The mixture was heated to 160° C. and kept at thistemperature for 1 hours. The epoxy resin K was obtained. The productcontained about 93 wt. % compound (I) and about 7 wt. % compound (V).

Comparative Example 4

57 parts by weight D.E.R.™ 331 and 43 parts by weight cardanol weremixed under nitrogen condition. After the mixture reached 90° C., 600ppm ethyl triphenyl phosphonium acetate (70 wt. % methanol solution) wasadded as catalyst. The mixture was heated to 160° C. and kept at thistemperature for 6 hours. The epoxy resin L was obtained. The productcontained about 3 wt. % compound (I) and about 97 wt. % compound (V).

III. Results Viscosity

5° C. 25° C. 25° C. 35° C. 45° C. 10% xylene 10% xylene Resin ResinResin solution solution Viscosity Viscosity Viscosity viscosityviscosity Examples State (cps) (cps) (cps) (cps) (cps) Epoxy resin ALiquid 11700 3168.7 1181.2 11250 940.3 Epoxy resin B Liquid 31000*7987.5 2887.3 15626 1750.5 Epoxy resin C Liquid 11900 3675.0 1368.711742 1108.7 Epoxy resin D Liquid 14150 4725.0 1668.7 12368 1566.2 Epoxyresin E Liquid NA 28200 8175.6 NA 9393.7 Epoxy resin F Liquid 32000*8287.5 3039.7 18525 2568.7 Epoxy resin G Liquid NA 36300 10024 NA 10550Epoxy resin H Liquid NA 26650 7575.1 NA 7250.5 Epoxy resin I Liquid937.5 242.5** NA 843.5 NA Epoxy resin J*** Solid NA NA NA NA NA Epoxyresin K Liquid 11057 3100.0 1024.5 10583 787.3 Epoxy resin L Liquid15500 5264.5 1985.3 15568 1623.4 D.E.R. ™ 331 Liquid 11150 3150.3 1057.510875 806.5 D.E.R. ™ 671- Solid NA NA NA NA 14306 X75**** *Testcondition: 6# rotator, 100 rmp; **Test condition: 6# rotator, 900 rmp;***The softening point of Epoxy Resin J is around 100° C.; Epoxy resin Jwas dissolved in 50 parts by weight xylene used in performance tests.****The softening point of D.E.R. ™ 671-X75 is from 75-85° C.;Commercially available product D.E.R. ™ 671-X75 was directly used forperformance tests. The supply form contains 75 parts by weight epoxyresins and 25 parts by weight xylene.

D.E.R.™ 671-X75 is a common epoxy resin used in anti-corrosion coating,which is solid state. Even using 25 parts xylene to dissolve 75 partsD.E.R.™ 671-X75, its solution viscosity is still very high (14306 cps).D.E.R.™ 671-X75 is not fit for low VOC high solids coating. Epoxy resinJ (Comparative Example 2) is also solid epoxy with even higher solutionviscosity than D.E.R.™ 671-X75. Thus, epoxy resin J cannot be used inlow VOC high solids coating as well. Epoxy resins modified by cardanol,or cardanol and dihydric phenol according to our technology are allliquid state. The viscosities of the resins solutions (90 parts byweight resin and 10 parts by weight xylene) are lower than D.E.R.™671-X75 (75 parts by weight D.E.R.™ 671 and 25 parts by weight xylene).As a result, the resin shows better workability compared with solidepoxy resin D.E.R.™ 671-X75 and can be used in coating formulation withhigher solids content.

Film Performance

90 weight by parts epoxy resins (besides epoxy resin J and D.E.R.™671-X75) was dissolved in 10 part by weight xylene and then was cured byCardolite™ NC 541LV. Epoxy resin J was dissolved in 50 parts by weightxylene. D.E.R.™ 671-X75 was directed used. Epoxy resin J (50% xylene)and D.E.R.™ 671-X75 were also cured by Cardolite™ NC 541LV. Thestoichiometry ratio of epoxy to amine is 1:1 for all the resins. Q-phospanel was used as substrate in most experiment, expect for Q panel usedfor anti-corrosion test. The paints were dried at 23° C. for 7 days.

1) Film Tack Free Time

Examples Film tack free time (h) Epoxy resin A 6.25 Epoxy resin B 6.5Epoxy resin C 7 Epoxy resin E 8 Epoxy resin G 10 Epoxy resin H 6 Epoxyresin I 19 Epoxy resin L 15

Film tack free time is a probe of drying time. The smaller value meansshorter drying time and faster drying speed, which is preferred.Comparative example epoxy resins I and L showed much slower drying thanother modified epoxy resins.

2) Pot Life

Examples Pot life (min) Epoxy resin A 35 Epoxy resin B 35 Epoxy resin C37 Epoxy resin D 39 Epoxy resin E 42 Epoxy resin F 45 Epoxy resin H 40D.E.R. ™ 331 31

Pot life suggested the operation window of paint. Longer pot life ispreferred. It was clear that modified epoxy shows improved pot lifecompared with liquid epoxy resin D.E.R.™ 331.

3) Hardness

Examples Pendulum Hardness (s) Epoxy resin A 130 Epoxy resin B 111 Epoxyresin C 100 Epoxy resin E 81 Epoxy resin H 115 Epoxy resin I 14 Epoxyresin L 35

Comparative example epoxy resin I and L were much softer than otherepoxy resins.

4) Wedge Bend

Examples Wedge bend (crack distance, cm) Epoxy resin A 0 Epoxy resin B 0Epoxy resin C 0 Epoxy resin D 0 Epoxy resin E 0 Epoxy resin F 0 Epoxyresin H 0 Epoxy resin K 4.6 D.E.R. ™ 331 6.0 D.E.R. ™ 671-X75 1.3

Wedge bend indicates flexibility of the films. Epoxy resin K, D.E.R.™331 and D.E.R.™ 671-X75 all showed crack after applying wedge bending,implying brittle films produced by them. Epoxy resins modified bycardanol, or cardanol and dihydric phenol show higher flexibility.

5) Impact Resistance

Impact resistance (4 pound * cm) Examples Front/back Epoxy resin A 35/20Epoxy resin B 70/55 Epoxy resin C 45/30 Epoxy resin D 55/50 Epoxy resinE 90/40 Epoxy resin F 65/50 Epoxy resin H 60/40 D.E.R. ™ 331 10/5 D.E.R. ™ 671-X75 30/20

Better impact resistance is found for epoxy resins modified by cardanol,or cardanol and dihydric phenol. D.E.R.™ 331 and D.E.R.™ 671-X75 showedlower impact resistance.

Anti-Corrosion Properties

Resin Epoxy resin C Epoxy resin I Time for 5 mm corrosion 700 48extension at scribe (h)

The salt spray resistance indicates that Epoxy resin I showed pooranti-corrosion properties.

Paint

Ingredients Weight percentage (%) Feldspar powder 41.4 Iron oxide 0.96Epoxy resin C 27.86 Butanol 2.00 Crayvallac super 1.88 Xylene 9.00Byk ®-A 530 0.11 Cardolite NC 541 12.05 Xylene 4.74

Films were applied using this paint. The dry film thicknesses of thefilms were all about 80 um. Q panel is used as substrate. The paintswere dried at 23° C. for 7 days.

Test items Performance Viscosity (cps, 1#, 200 rmp) 644 Film tack freetime (h) 4.5 Pot life (min) 63 Hardness (s) 67 Wedge bend (crackdistance, cm) 2.8 Impact resistance (4 pound * cm, Front/back) 25/5Anticorrosive performance Good

1. A process for preparing the epoxy resin composition, the epoxy resin composition comprises the following resins based on the total weight of the epoxy resin composition, i. from 10% to 75% by weight of a liquid epoxy resin of formula (I):

wherein n is 0 or 1; each R is independently H or —CH₃; and R₁ is —C₁₅H₂₅, —C₁₅H₂₇, or —C₁₅H₂₉; ii. from 10% to 75% by weight of a compound of formula (V):

wherein n is 0 or 1; each R is independently H or —CH₃; and R₁ is —C₁₅H₂₅, —C₁₅H₂₇, or —C₁₅H₂₉; and iii. from 10% to 70% by weight of a compound of formula (VI):

wherein x is 1 or 2; each n is independently 0 or 1; each R is independently H or —CH₃; and R₁₁ by formula (VII):

wherein R₂ is independently H or a C₁-C₁₅ alkyl or alkenyl group; the method comprises admixing a liquid epoxy resin of formula (I) and a cardanol moiety.
 2. The process of claim 1, wherein the liquid epoxy resin of formula (I) comprises 60% to 95% by weight based on the total weight of the mixture of a diglycidyl ether of a bisphenol.
 3. The process of claim 2, wherein the diglycidylether of bisphenol is chosen from a group of the diglycidylether Bisphenol A, the diglycidylether Bisphenol F, and combinations thereof.
 4. The process of claim 2, wherein the liquid epoxy resin of formula (I) is in liquid state without adding any solvent.
 5. The process of claim 1, wherein the epoxy resin composition is optionally reacted with a dihydric phenol.
 6. The process of claim 4, wherein the dihydric alcohol is chosen from a group of cardanol, bisphenol A, bisphenol F, resorcinol, or combinations thereof.
 7. The process of claim 1, wherein a catalyst is optionally added.
 8. The process of claim 7, wherein the catalyst is selected from a group comprising a basic inorganic reagent, a phosphine, a quaternary ammonium compound, phosphonium reagents, tertiary amines, and combinations thereof.
 9. The process of claim 8, wherein the catalyst is triphenylphosphonium acetate.
 10. The process of claim 1, wherein the process is conducted in the absence of solvent.
 11. The process of claim 1, wherein the temperature ranges from 20° C. to 260° C. 